1. Field of the Invention
The present invention relates to electronic components. In particular, the present invention relates to an electronic component such as a monolithic ceramic capacitor.
2. Description of the Related Art
In recent years, a reduction in size and an increase in functionality of electronic devices has rapidly progressed. Electronic components mounted on the electronic devices are also desired to be reduced in size. For example, a monolithic ceramic capacitor having a large electrostatic capacity is commercially produced as an alternative to an aluminum electrolytic capacitor because of the progress of a thin-layer technique and a multi-layer technique.
Referring to FIG. 10, a monolithic ceramic capacitor 1 includes a base member 4 in which a plurality of ceramic layers 2 and a plurality of internal electrodes 3 are alternately stacked. Adjacent internal electrodes 3 of the plurality of internal electrodes 3 are alternately led to opposed end surfaces of the base member 4. External electrodes 5 are formed on the end surfaces of the base member 4 to which the internal electrodes 3 are led. The external electrodes 5 are electrically connected to the internal electrodes 3. With this configuration, an electrostatic capacity is formed between the external electrodes 5 provided at the opposed end portions of the base member 4. The monolithic ceramic capacitor 1 is attached to a substrate 7 with solder 6. At this time, the external electrodes 5 of the monolithic ceramic capacitor 1 are attached to the substrate 7 with the solder 6.
The material of the ceramic layers 2 of the monolithic ceramic capacitor 1 is typically a ferroelectric material such as barium titanate with a relatively high dielectric constant. However, the ferroelectric material has piezoelectricity and electrostriction. If an alternating voltage is applied to the monolithic ceramic capacitor 1, a mechanical strain is generated at the ceramic layers 2. If vibration caused by the strain is transmitted to the substrate 7 through the external electrodes 5, the entire substrate 7 may serve as an acoustic radiation surface and hence generate vibration sound such as noise or chatter.
To address this, a configuration as shown in FIG. 11 is suggested, in which a pair of metal terminals 8 are connected to the external electrodes 5 of the monolithic ceramic capacitor 1 with solder and the metal terminals 8 are connected to the substrate 7 by soldering such that the a gap is provided between the substrate 7 and the monolithic ceramic capacitor 1. With this configuration, elastic deformation of the metal terminals 8 can absorb the mechanical strain, which is generated at the ceramic layers when the alternating voltage is applied, restrict transmission of the vibration to the substrate through the external electrodes, and hence reduce generation of the noise (see Japanese Unexamined Patent Application Publication No. 2004-288847, FIG. 21).
However, even when the configuration in which the monolithic ceramic capacitor is attached to the substrate by using the metal terminals is used, an effect of sufficiently restricting the vibration sound of the substrate is not attained.